相关论文: Does the CO-to-H2 conversion factor depend on the …

We use the IRAM HERACLES survey to study CO emission from 33 nearby spiral galaxies down to very low intensities. Using atomic hydrogen (HI) data, mostly from THINGS, we predict the local mean CO velocity from the mean HI velocity. By…

We present Herschel PACS observations of the [CII] 158 micron emission line in a sample of 24 intermediate mass (9<logM$_\ast$/M$_\odot$<10) and low metallicity (0.4< Z/Z$_\odot$<1.0) galaxies from the xCOLD GASS survey. Combining them with…

The CO-H2 conversion factor in galaxies is typically described as bimodal: one value for discs and quiescent regions, and another (lower) value for mergers and starbursts. In this proceeding, I will describe both empirical observational…

A new method to determine the CO-to-H$_2$ conversion factor $X_{\rm CO}$ using absorption of diffuse X-ray emission by local molecular clouds was developed. It was applied to the Ophiucus (G353+17) and Corona Australis (G359-18) clouds…

We present an analysis of the relationship between the CO-H$_{2}$ conversion factor ($\alpha_{\rm CO}$) and total mass surface density ($\Sigma_{\rm tot}$) in star-forming galaxies at $z < 1.5$. Our sample, which is drawn from the IRAM…

The Kennicutt-Schmidt (K--S) law in IC 342 is examined using the 12CO-to-H2 conversion factor (Xco,v), which depends on the metallicity and CO intensity. Additionally, an optically thin 13CO (1-0) is also independently used to analyze the…

Determining how galactic environment, especially the high gas densities and complex dynamics in bar-fed galaxy centers, alters the star formation efficiency (SFE) of molecular gas is critical to understanding galaxy evolution. However,…

We use the Arepo moving mesh code to simulate the evolution of molecular clouds exposed to a harsh environment similar to that found in the galactic center (GC), in an effort to understand why the star formation efficiency (SFE) of clouds…

We measure the radial profile of the 12CO(1-0) to H_2 conversion factor (Xco) in NGC 628. The H\alpha emission from the VENGA integral field spectroscopy is used to map the star formation rate surface density (\Sigma_{SFR}). We estimate the…

We present numerical simulations of molecular clouds (MCs) with self-consistent CO gas-phase and isotope chemistry in various environments. The simulations are post-processed with a line radiative transfer code to obtain $^{12}$CO and…

Carbon monoxide (CO) emission is a widely used tracer of molecular hydrogen (H$_2$) in the interstellar medium (ISM), owing to its abundance, low excitation energy, and ease of detection in cold molecular environments, in contrast to…

We made CO(1-0) observations of 103 lines of sight in the core and envelope of the high-latitude cloud MBM 40 to determine how the CO-H_2 conversion factor (X_CO) varies throughout the cloud. Calibrating X_CO with CH data at similar…

Properties of candidate stars, forming out of molecular clouds, depend on the ambient conditions of the parent cloud. We present a series of 2D and 3D simulations of fragmentation of molecular clouds in starburst regions as well as clouds…

In this paper we investigate the level of star formation activity within nearby molecular clouds. We employ a uniform set of infrared extinction maps to provide accurate assessments of cloud mass and structure and compare these with…

Tracing molecular hydrogen content with carbon monoxide in low-metallicity galaxies has been exceedingly difficult. Here we present a new effort, with IRAM 30-m observations of 12CO(1-0) of a sample of 8 dwarf galaxies having oxygen…

We present radial profiles of surface brightness in UV and IR bands, estimate stellar mass surface density ($\Sigma_\star$) and star formation rate surface density ($\Sigma_\mathrm{SFR}$), and predict the CO-to-H$_2$ conversion factor…

We compute the star formation rate (SFR) in molecular clouds (MCs) that originate {\it ab initio} in a new, higher-resolution simulation of supernova-driven turbulence. Because of the large number of well-resolved clouds with…

A steep metallicity dependence of the CO-to-H2 conversion factor X of the form log X = 12.2 - 2.5 log[O]/[H], based on a sample of 20 (extra)galactic determinations, is presented and discussed. The apparently less steep dependence found…

High-resolution CO maps of 9 molecular clouds in IC 10 are combined with the new measurement of the distance to this nearby metal poor galaxy to measure accurately the CO-to-H2 conversion factor. The result for IC 10 is combined with…

We present an analytical determination of the star formation rate (SFR) in molecular clouds, based on a time-dependent extension of our analytical theory of the stellar initial mass function (IMF). The theory yields SFR's in good agreement…